lots of early braking. Start braking early enough so you get all the bars lit, but no harder than that. This way you'll maximize the time that you are recharging. But for better overall FE, start coasting even earlier and use no brakes. Put it in Neutral if you don't think you'll necessarily be stopping (timing a light, etc).

DO NOT WORRY ABOUT ONLY HAVING 3-4 BARS!!! Completely normal. Any system that is being constantly partially replenished and depleted will average out to around 1/2.